1. Field of the Invention
The present invention relates to a method for indicating battery life and a computer readable recording medium and, more particularly, to a method for indicating battery life of an electronic device typified by an electronic watch having an exclusive-use microcomputer IC therein, the method being capable of adjusting an indication reference of the battery life so that a voltage necessary for the operations of all functions can be determined.
2. Description of the Prior Art
In recent years, electronic watches have many functions. For example, wristwatches each having watch auxiliary functions such as alarm, chronograph, timer, and the like, an altimeter function, and the like separately from watch functions have been manufactured. Since the altimeter function measures an altitude on the basis of a change in atmospheric pressure by detecting the atmospheric pressure through a pressure sensor, it requires a voltage higher than that of the general watch function or watch auxiliary function.
On the other hand, in electronic devices such as electronic watches or the like to which a power supply is supplied by a battery, has been known a method for indicating battery life in such a manner that the battery life is determined on the basis of a voltage of the battery and is displayed. According to the indicating method, a comparator built in an exclusive-use microcomputer IC for controlling the watch functions of the electronic watch detects the battery voltage, compares the voltage with a preset reference voltage, determines the battery life, and indicates the life.
There have been known electronic devices for displaying the indication. For example, there have been known electronic devices, in which a character modeled on a dry battery is divided into three portions, for indicating that an enough voltage is stored when all of the divided portions are displayed, and sequentially turning off the display portions as the voltage is reduced, thereby indicating battery life.
In the conventional method for indicating battery life, however, since the comparator built in the exclusive-use microcomputer IC determines the battery life to indicate it, only voltages within a restricted range according to the detection resolving power of the comparator can be determined.
The conventional method for indicating battery life is designed so as to set a low voltage necessary for the watch function or watch auxiliary function as a reference. Accordingly, in a case of the altimeter function requiring a voltage higher than that for the watch function or watch auxiliary function, in spite of such a display that the battery life is not exhausted, it is not a necessary voltage in some cases. In this case, when the altimeter function is executed, the function may not be normally operated or the battery may run down during the execution of the altimeter function.
That is, the detection resolving power of the comparator built in the exclusive-use microcomputer IC is generally equal to xc2x10.1[V]. Even when it is varied depending on software or the like, a value which can be set as a reference value is limited to 2.4[V], 1.8[V], 1.2[V], or 1.05[V]. For instance, when a detection voltage is set to 2.4[V], an actual detection voltage is in a range from 2.3 to 2.5 [V], namely, a detection range of 0.2[V]. The value can be set only within a range according to mass production variation. Accordingly, in the case of the function such as watch function or watch auxiliary function which can use even the low voltage, when the detection resolving power of the comparator is equal to xc2x10.1[V], enough battery life can be maintained. However, in the electronic watch with heavy loads, for example, with the altimeter function accompanied with atmospheric pressure detection through a pressure sensor, the low limit value (about 2.4[V]) of the operation voltage of the function is higher than that (about 1.1[V]) of the general function of the electronic watch. Therefore, the function is not normally operated or battery exhaustion occurs.
The present invention is made in consideration of the above problems and it is an object of the invention to provide a versatile method for indicating battery life of an electronic device typified by an electronic watch having an exclusive-use microcomputer IC therein, the method being capable of easily adjusting an indication reference of the battery life according to a function so as not to cause such a situation that the function is not normally operated or battery exhaustion occurs.
To accomplish the above object, according to the invention, a method for indicating battery life comprises: an indication reference adjusting mode step including a reference voltage converting step of generating a minimum driving voltage value necessary for the operations of all functions of an electronic device as a reference voltage of an analog quantity and of inputting the voltage value into an A/D converting circuit to convert the value into a digital value, and a reference value storing step of storing a digital value outputted from the A/D converting circuit as a reference value corresponding to a voltage value necessary for each processing mode of the electronic device; a battery life indicating mode step including a battery voltage converting step of inputting the voltage value of a battery as an analog quantity to the A/D converting circuit to convert the value into a digital value, a reference value reading step of reading out the reference value previously stored, a comparing step of comparing the digital value outputted from the A/D converting circuit with the reference value, and a battery life determination indicating step of determining battery life necessary for the operations of all functions on the basis of the comparison result to indicate the battery life; and a mode switching control step of controlling to switch the mode between the indication reference adjusting mode and the battery life indicating mode.
Consequently, the indication reference of the battery life can be adjusted according to all functions of the electronic device typified by an electronic watch, which has an exclusive-use microcomputer IC therein. Therefore, according to the invention, since the reference voltage according to the function can be easily set, a versatile method for indicating battery life can be provided. Consequently, the function can be normally operated and the occurrence of battery exhaustion can be prevented during the operation of the function. The indication reference can be adjusted without needing a high speed adjusting device for controlling the A/D converting circuit or writing data to an EEPROM on a circuit block.
Preferably, the mode switching control step includes a synchronization signal switching step of switching the mode to the indication reference adjusting mode on the basis of a synchronization signal from an adjusting device, the adjusting device comprising: a stabilized power supply for generating an arbitrary voltage value as an analog quantity as a reference voltage and for outputting the voltage to the A/D converting circuit; and control means for outputting the generated reference voltage and for outputting the synchronization signal. The synchronization signal switching step may include a reset input switching step of, when a reset input is supplied to the electronic device in addition to the synchronization signal, switching the mode to the indication reference adjusting mode.
Further, an electronic device according to the invention is characterized by using the above-mentioned method for indicating battery life.
A computer readable recording medium of the invention may be characterized by storing a program which allows a computer to execute the foregoing method for indicating battery life.
The xe2x80x9ccomputer readable recording mediumxe2x80x9d means a portable medium such as floppy disk, magneto-optical disk, ROM, CD-ROM, or the like, and a recording device such as hard disk or the like, which is installed in a computer system. Furthermore, the xe2x80x9ccomputer readable recording mediumxe2x80x9d includes a medium such as a communication line for transmitting a program through a network such as the Internet or the like or a communication line such as a telephone line or the like, which dynamically holds a program for a short time, and also includes a medium such as a volatile memory in a computer system serving as a server or a client in this case, which holds a program for a predetermined period. The above program may realize a moiety of the above-mentioned functions and may realize the foregoing function by combining with a program previously stored in the computer system.
As the foregoing A/D converting circuit, for example, an A/D converting circuit for sensor detection, which converts an output of a pressure sensor for measuring a pressure into a digital value at the time of an altimeter function, as disclosed in Japanese Patent Application Laid-Open No. 9-318403/1997 is preferably used.